toe soy te Mf Bae cr re 3NL-=2E9 59 Thvrale Absorsed Dose AssSessmene for Rongeiaod and VUcirik Resicents E.T. Lessard, J.R. Naidu, &.P. Miltenberger 3rooxnaven National Laboratory Satety and Environmental Procection Division Upton, New York 410419 11973 & N.A. Greenhouse University of California Lawrence Berkeley Laboratory Berkeley, California 94720 o L.V. Xaplan Srooxhaven Summer Studenc Program 3rookhaven National Laboratory and Yale Universicy ABSTRACT The incernal thyroid absorbed dose from Castle Bravo fallouc affecring Rongelap and Utirik Arolls, Marshall Islands, indecendenc approacnes encompassing 1) is reassessed using . che single nooled urine radio- chemical analysis of March 1954 and currenc uptake, retention and excrerion models, 2) airborne concencrations and areal activities of the iodine isotopes derived from historic soil samples and, 3) and areal activities of atrborne concenctrarcions the todine isotopes derived from weather daca ab- tained during the thermonuclear test experimenc ac Bikini Atol2 and current fallout deposicion meceis. Factors such as solubilicy of Lodine isotopes, the possible contribution from neucron induced activity, the impact of chy- roid seekers other than iodine isotopes on dose, and confidence levels for vaiues of derived quantities such as airborne accivicy concenctracions are also considered. Additionally, these thyroid absorbed dose estimates are compared to che incidence of thyroid nodules reported for the accidentally exposed people. BEST COPY AVAILABLE Research carried out under che auspice of the U. under Contrace No. DE-AC92-74CHO0016. $. Deparemenc of Energy